Portable fan



FIG. 1 is a front right isometric view of a portable fan showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a right-side view thereof;

FIG. 6 is a left-side view thereof; and,

FIG. 7 is a back view thereof. 

CLAIM The ornamental design for a portable fan, as shown. 